<div class="search-brank">
                <label style="cursor:pointer;"  @click="search"><i class="icon-date"></i></label>
                <el-date-picker
                 :editable='false'
                    v-model="datetime"
                    type="daterange"
                    unlink-panels
                    class="datePickers" start-placeholder="开始日   期" end-placeholder="结束日期" 
                    @change="handleDate"
                    :picker-options="pickerOptions0" clearable>
                </el-date-picker>
            </div>

赋值函数：

            handleDate(){
                if(this.datetime[0]!=null){
                     this.starttime=this.formDate(this.datetime[0]);
                    this.endtime=this.formDate(this.datetime[1]);
                }else{
                     this.starttime='';
                     this.endtime='';
                }
            },

问题：当控件清空或修改时，@change=“handleDate”不会触发，datetime并不会实时更新。并且实际上，如果清空了datetime是null，并没有this.datetime[0]=null，this.datetime[1]=null的说法。
解决：使用@input=“immediUpdate”。

 <div class="search-brank">
                <label style="cursor:pointer;"  @click="search"><i class="icon-date"></i></label>
                <el-date-picker
                 :editable='false'
                    v-model="datetime"
                    type="daterange"
                    unlink-panels
                     class="datePickers" start-placeholder="开始日   期" end-placeholder="结束日期" 
                    @input="immediUpdate"
                    :picker-options="pickerOptions0" clearable>
                </el-date-picker>
             </div>

            immediUpdate(e) {
                this.$nextTick(() => {
                    if(e==null){
                        this.starttime='';
                        this.endtime='';
                    }else{
                        this.$set(this,"datetime", [e[0], e[1]]);
                        this.starttime=this.formDate(this.datetime[0]);
                        this.endtime=this.formDate(this.datetime[1]);                        
                    }

                });
            },